Pan-type oil burner



Sept. 3, 1963 w. DURR PAN-TYPE. OIL BURNER Filed July 18, 1960 INVENrOIP 4! 041%,- per,

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United States Patent 3,102,578 PAN-TYPE OIL BURNER Walter Diirr, Uberlingen (Bodensee), Germany, assignor to Motan G.m.b.H., Uberlingen (Bodensee), Germany, a corporation of Germany Filed July 18, 1960, Ser. No. 43,616 Claims priority, application Germany July 16, 1959 8 Claims. (Cl. 158-67) The present invention relates to an oil burner of the pan type which is provided with a combustion chamber above the burner pan and an oil feed pipe terminating into the burner pan. More particularly, the invention relates to a pan-type oil burner in which a nozzle head for supplying the combustion air isprovided on an airsupply pipe extending through the burner pan and at a point within the combustion chamber above the burner pan and the oil feed pipe.

The pan-type oil burners of this kind which are presently known have the disadvantage that under certain circumstances oil residues may form within the lower part of the combustion chamber and especially Within the area underneath the bell-shaped part of the burner or on the outlet opening for the oil. Such residues are due to the fact that the oil is maintained at too low a temperature at these points. The oil therefore is not completely vaporized and a cracking process occurs which results in the formation of the residues.

It is an object of the present invention to provide a pan-type oil burner in which the oil is at all times completely vaporized, and in which the emerging oil vapor will always be mixed at the proper ratio withthe combustion air.

It is therefore a more specific object of the invention to provide a pan-type oil burner which is designed so as to insure that the temperature of the oil will always be a few degrees above its boiling point. It is therefore an essential feature of the oil burner according to the invention that those parts of the burner with which the oil vapor comes into contact will be heated to a temperature above the boiling point of the fuel oil.

In order to obtain a complete vaporization of the fuel oil, the invention provides a highly heat-conductive connecting element which projects from the combustion chamber into the conduit through which the oil is being supplied. By means of this heat-conductive element, the intense heat developed in the combustion chamber will be transmitted to the oil flowing, into the burner pan with the result that the oil will already be completely vaporized when it enters into the burner pan.

For a preferred design of u pan-type burner, in which for supplying the combustion air the burner is provided in a manner known as such with an air inlet pipe which extends through the burner pan and with a nozzle head on the end of the air-inlet pipe within the combustion chamber at a point above the burner pan and the oil feed pipe, the present invention provides a metallic element which is inserted into an aperture in the upper wall of the nozzle head and also passes through the bottom of. the nozzle head and projects into the oil feed pipe. This metallic element preferably extends centrally within the upper end of the oil feed pipe and coaxially thereto in a manner so that during its flow to the burner pan the oil will come into contact with the heat-conductive element along a large surface area thereof.

According to another feature of the invention, the airinlet channel extends coaxially with and through the heatconductive element to a point within the head thereof which is disposed within the nozzle head and is provided with air distributing channels which connect the central air-inlet channel with the inside of the nozzle head so that the combustion air will pass freely from the air-inlet channel into the nozzle head.

It is further advisable according to the invention to provide an annular recess between the air-inlet channel and the cylindrical extension of the heat-conductive element and to connect this annular recess by means of transverse vent bores in this extension with the combustion chamber underneath the nozzle head. These vent bores are necessary since the nozzle head is fitted only loosely over the air inlet pipe and the possibility may therefore arise that some of the oil vapor will creep upwardly along the inside of the air inlet pipe and enter into the chamber within the nozzle head where it may cause explosions. By providing the heat-conductive element with such vent bores, the oil Vapor which is formed around the air inlet pipe will be able to escape into the area underneath the nozzle head and will not enter into the nozzle head itself, so that the danger of any explosions within the nozzle head will be absolutely prevented.

In the event that in a particular construction of theoil burner according to the invention the oil will not be heated as quickly as desired to the required temperature at the point of its vaporization, it is advisable to extend the heat-conductive element upwardly for a considerable extent into the combustion chamber so that this element will be additionally heated as much as possible by the heat which is developed within the combustion chamber.

According to still another feature of the invention it is possible to accelerate the heating action .of the heat-conductive element by providing it with electric means, and it is also possible to provide electricrneans for igniting the mixture of oil vapor and combustion air. I These and other objects, features, and advantages of the present invention will become further apparent from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which: a

FIG. 1 is a central section of a pan burner according to the present invention taken in axial direction thereof;

and

FIG. 2 is a partial cross section through a burner as shown in FIG. 1 and illustrating a modified part of this burner.

Referring first to FIG. 1 of the drawing, it will be seen that the pan burner according to the present invention consists of a cylindrical jacket 1 with a bottom 2 thereon which forms a burner pan. This burner pan 2 has a central aperture 21:, the wall of which is connected to the upper end of a short oil feed pipe 3 which carries near its lower end a connecting piece 4 to which an oil feed line, not shown, may be connected. Feed pipe 3 has centrally mounted therein and extending therethrough a pipe 5 for supplying the combustion air. A nozzle head 7 is mounted within the combustion chamber 8 above the burner pan 2 by being loosely fitted over the air inlet pipe 5. I

Nozzle head 7 is designed so as to divide the space above the burner pan 2 into two parts, namely, the comhustion chamber.8 and a vaporizing chamber .8, and in a manner so that a very narrow, preferably annular gap 9 remains between the two chambers 8 and 8. For this purpose, the central part 1011 of the lower wall 10 of nozzle head 7 is drawn upwardly to form a first bell shaped portion 10, while the outer edge 10b of-the nozzle head is drawn downwardly so to be disposed at a small distance from the burner pan 2.

In order to vaporize the oil as completely as possible before it enters into burner pan 2, the invention provides an element 11 with high heat conductive properties which is therefore adapted to transmit as much heat as possible to the point where the oil is to be vaporized. According to the embodiment of the invention as shown in FIGURE second bell shaped portion 13 of nozzle head 7. This head portion 12 of element 11 is further secured in the wall of the first bell shaped portion 10" of nozzle head 7 and its tubular extension 11 projects downwardly into the oil teed pipe 3. Due to the heat-conductive properties of element 11, the oil will be vaporized from its surface in pan 2, and the amount so vaporized depends upon the volume of heat and the amount of oil which is supplied to pan 2. The heat volume must be determined so that even at a maximum output of the oil stove there will still be sufiicient heat available for vaporizing the oil so that substantially no liquid oil will be supplied into burner pan 2.

The air passes through passage means formed by the air inlet pipe and the transverse bores 14 in element ll to the chamber formed between the bell shaped portions and 13 of the nozzle head from which it may pass through the outlet openings 15 and 16 into the combustion chamber. Due to the constriction at 9, the emerging airWill be thoroughly mixed with the oil vapor emerging from the chamber 8' underneath the nozzle head 7. Since the nozzle head 7 is only loosely fitted over the air inlet pipe 5, care must be taken that no oil vapor will creep upwardlyalong the air inlet pipe and enter into the chamber which is formed within the bell-shaped nozzle head 7, since there Will otherwise be the danger that the oil vapor will become mixed with the air contained therein and that undesirable combustions and explosions will occur at the inside of the nozzle head. In order to avoid this, the invention further provides the lower cylindrical part of the heat-conductive element 11 With a plurality of vent bores 17 through which the oil vapor may pass into the'chamber underneath the nozzle head 7.

The eifect of bores 17 is the following: Due to the chimney draft, there will be an underpressure in the combustion chamber. The heat-conductive element 11 and the air inlet pipe 5 are separated by a narrow gap 11" so that a considerable throttling effect will be produced at this point as well as at the outlet openings 16. Due to this throttling eifect, the oil vapor which rises in the annular gap 11" will be continuously drawn off through the transverse bores 17, andvit will thus be absolutely prevented that any oil vapor will enter into the chamber within the bell-shaped nozzle head 7.

Above the nozzle head 7, a burner ring 18 is mounted on the inner wall of jacket 1. This burner ring tapers upwardly from jacket 1 toward the center of the burner and it confines the flame, which is formed in the lower part of the burner at a point directly above the burner pan 2, within the combustion chamber .8. Due to its tapering shape, burner ring 18 also reflects the combustion gases against the walls of nozzle head 7 so that the latter will at all times be heated to a high temperature and will thus always insure that the combustion air passing into thenozzle headwill be sufliciently preheated. A handle strap B is connected to the upper Wall 13 of the nozzle head 7 and extending upwardly through the burner ring 18.

Due to the inventive arrangement of a heat conductive element which extends from the combustion chamber,

, preferablyrfrom the upper wall of nozzle head 7, into the oil inlet pipe, it is possible to prevent the formation of any residue in the burner pan 2 so that the latter willremain perfectly clean. The heat conductor is preferably extended for a certain distance beyond the lower bottom of the nozzle head so that a sufiicient surface area In such "a case it is possible to extend head portion 12' of the heat-conductive element in the upward direction into the combustion chamber, for example, in the manner ,as indicated in FIG. 2, or even to provide it with lateral extensions in order to attain a large surface for absorbing the heat from the combustion chamber and for transmitting the same as quickly as possible to the oil inlet passage. When extending the heat-conductive element into the combustion chamber, its upper end may also be used as a handle portion, and it is then possible to omit the handle strap B. I

It is likewise within the concept of the present invention to provide additional means for heating the heatconductive element, for example, by means of an electric current. It will thus be possible to attain the required temperature very quickly at the place of vaporization of the oil. The heat-conductive element may then, for example, ibe heated electrically at least at the start of the operation of the stove. According to a further feature of the invention, the mixture of 'oil vapor and combustion air may then also be ignited electrically.

Although my invention has been illustrated and described wi-th reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. A pan type oil burner comprising, in combination, a burner pan; a combustion chamber above said pan; an oil feed conduit terminating in said pan; a nozzle head disposed within said combustion chamber above said pan and s'aid'oil feed conduit and including an elongated central element of highly heat conductive material having an upper portion extending upwardly into said combusportion, said bell shaped portion having a lower edge spaced from said panuand forming with the latter an annular gap through which the vaporized oil passes from said vaporizing chamber into said combustion chamber; and passage means extending with a lower portion through said elongated central element of said nozzle head and with an upper portion thereof about said head portion of said elongated element for feeding combustion air into the regionof said annular gap so that combusion air passing through said passage means is preheated before it mixes with the vaporized oil passing through said gap.

2. A pan type oil burner comprising, in combination, a burner pan; a combustion chamber above said pan; an oil feed conduit terminating in said pan; a nozzle head disposed within said combustion chamber above said pan and said oil feed conduit and including an elongated central portion of highly heat conductive material extending upwardly into said combustion chamber to be heated therein and downwardly into said oil feed conduit to transmit heat .from the combustion chamber to the oil passing through said oil feed conduit so as to vaporize the oil passing therethrough before it reaches said pan, a first bell shaped portion located above said pan and surrounding part of said elongated portion to form a vaporizing chamber about said elongated portion, said first bell shaped portion having a lower edge spaced from said pan and forming with the latter an annular gap through which the vaporized oil passes from said vaporizing chamber into said combustion chamber, and a second bell shaped portion located above and about said first bell shaped portion and being connected thereto in the region of the lower edge of the latter to form a substantially closed chamber therewith communicating with said gap through openings formed in at least one of said bell shaped portions; and air passage means extending through said oil feed conduit and through said elongated portion of said nozzle head and communicating with the chamber formed by said bell shaped portions.

'3. A pan type oil burner comprising, in combination, a burner pan; a combustion chamber above said pan; an oil feed conduit terminating at a substantially central portion of said pan; a nozzle head disposed within said combustion chamber above said pan and said oil feed conduit and including an elongated central portion of highly heat conductive material having an upper portion located in said combustion chamber to be heated therein and .a lower portion extending at least in part into said oil feed conduit to transmit heat from said heated upper portion to the oil passing through the oil feed conduit so as to vaporize the oil passing therethrough before it reaches said pan, a first bell shaped member located above said pan about said elongated central member substantially coaxial therewith to form a vaporing chamber about said elongated member, said first bell shaped portion having a lower edge spaced from said pan and forming with the latter an annular gap through which the vaporized oil passes from said vaporizing chamber into said combustion chamber, a second bell shaped portion located above and about said first bell shaped portion and being connected thereto in the region of the lower edge of the latter to form a substantially closed chamber therewith communicating with said gap through openings formed in at least one of said bell shaped portions, said elongated member being formed with a central bore extending from the lower toward but short of the upper end thereof and with at least a transverse bore communicating with said central bore and said closed chamber; and a conduit passing through said oil feed conduit into said central bore of said elongated central member of said nozzle head for feeding combustion air into said central bore and from there through said transverse bore into said closed chamber and through said openings into said annular gap so that air will mix in said annular gap with the vaporized oil passing therethrough.

4. An arrangement as defined in claim 3 in which a lower portion of said central bore is formed with an inner diameter greater than the outer diameter of the conduit passing therethrough, and including at least one transverse bore communicating at one end with said lower portion of said central bore and at the other end with the interior of said vaporizing chamber.

5. A pan type oil burner comprising, in. combination, a burner pan; a combustion chamber above said pan; an oil feed conduit terminating in said pan; a nozzle head disposed within said combustion chamber above said pan and said oil feed conduit and including an elongated central portion of highly heat conductive material extending upwardly into said combustion chamber to be heated therein and downwardly into said oil feed conduit to transmit heat from the combustion chamber to the oil passing through said oil feed conduit so as to vaporize the oil passing therethrough before it reaches said pan, a first bell shaped portion located above said pan and surrounding part of said elongated portion to form a vaporizing chamber about said elongated portion, said first bell shaped portion having a lower edge spaced from said pan and forming with the latter an annular gap through which the vaporized oil passes from said vaporizing chamber into said combustion chamber, and a second bell shaped portion located above and about said first bell shaped portion and being connected thereto in the region of the lower edge of the latter to form a substantially closed chamber therewith communicating with said gap through openings formed in at least one of said bell shaped portions; and air passage means communicating with the chamber formed by said bell shaped portions.

6. An arrangement as defined in claim 5 in which said burner pan has a peripheral outer edge, and including a jacket extending upwardly from said outer edge of said burner pan; and conical ring means mounted on said jacket and converging from the inner surface thereof in upward direction for directing flames in the combustion chamber toward said second bell shaped portion of said nozzle head.

7. In an arrangement as defined in claim 5 in which said elongated central portion of said nozzle head extends through and upwardly beyond said second bell shaped portion of said nozzle head.

8. An arrangement as defined in claim 5 in which said first and second bell shaped portions of said nozzle head are formed from sheet metal.

References Cited in the file of this patent UNITED STATES PATENTS 2,181,500 Behrsin Nov. 28, 1939 FOREIGN PATENTS 423,979 Great Britain Feb. 12, 1935 1,196,397 France May 25, 1959 

1. A PAN TYPE OIL BURNER COMPRISING, IN COMBINATION, A BURNER PAN; A COMBUSTION CHAMBER ABOVE SAID PAN; AN OIL FEED CONDUIT TERMINATING IN SAID PAN; A NOZZLE HEAD DISPOSED WITHIN SAID COMBUSTION CHAMBER ABOVE SAID PAN AND SAID OIL FEED CONDUIT AND INCLUDING AN ELONGATED CENTRAL ELEMENT OF HIGHLY HEAT CONDUCTIVE MATERIAL HAVING AN UPPER PORTION EXTENDING UPWARDLY INTO SAID COMBUSTION CHAMBER TO BE HEATED THEREIN AND A LOWER PORTION EXTENDING DOWNWARDLY INTO SAID OIL FEED CONDUIT TO TRANSMIT HEAT FROM THE COMBUSTION CHAMBER TO THE OIL PASSING THROUGH SAID OIL FEED CONDUIT SO AS TO VAPORIZE THE OIL PASSING THERETHROUGH BEFORE IT REACHES SAID PAN, AND A BELL SHAPED PORTION LOCATED ABOVE SAID PAN AND SURROUNDING PART OF SAID UPPER PORTION OF SAID ELONGATED ELEMENT TO FORM A VAPORIZING CHAMBER ABOUT SAID PART OF SAID UPPER PORTION OF SAID ELONGATED ELEMENT WHICH EXTENDS WITH A HEAD PORTION UPWARDLY BEYOND SAID BELL SHAPED PORTION, SAID BELL SHAPED PORTION HAVING A LOWER EDGE 